An exchange student from Switzerland, who is male, has been assigned to be your partner in an introductory psychology class. As part of a class assignment, he responds to your question about his family by stating only that he comes from a family of two children, without specifying whether he is the older or the younger. What is the probability that his sibling is female? Assume equal probability of hav- ing a boy or girl. Why does this result seem counterintuitive at ?rst?